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Intrapartum Management

ACTIVE MANAGEMENT OF LABOR

Active management of labor is a system of labor management for nulliparous women. It has been advocated as a potential strategy to reduce the rate of cesarean deliveries. Active management of labor is confined to nulliparous women in spontaneous labor with singleton cephalic presentations and in whom there is no evidence of fetal com plications. Active management of labor, as developed and practiced in Ireland, does not include multiparas or women undergoing induction of labor. It involves several distinct entities: 1) patient education; 2) strict criteria for the diagnosis of labor; 3) strict criteria for abnormal progress in labor; 4) high-dose oxytocin; 5) a personal nurse in labor; 6) strict criteria for FHR monitoring and diagnosis of fetal distress; 7) specific indications for operative deliveries; and 8) peer review of cesarean deliveries. Many American obstetricians have focused on the use of high-dose oxytocin as the means to achieve this apparently low cesarean rate. It is important to emphasize that high-dose oxytocin is just one part of the active management of labor. In fact, most women managed with active management of labor do not even receive oxytocin.

Women are instructed during pregnancy as to signs and symptoms of labor and are encouraged to present early in labor. The diagnosis of labor is made initially by the woman herself and is confirmed by a health care provider. Confirmation depends on painful uterine contractions and one of the following: passage of a mucus plug, complete effacement, or spontaneous rupture of membranes. Progress in labor during the first stage is measured in terms of cervical dilatation only. Progress in the second stage is a function of time and is abnormal if longer than 2 hours. Membranes are ruptured, if intact, at 1 hour after admission. A vaginal examination is performed hourly, and oxytocin infusion is begun if there is not a change of at least 1 cm in dilatation since the last induction of labor, Pitocin, oxytocin, fetal heart rate monitoring, forceps, vacuum extraction, cesarean, vaginal birth after cesarean, VBAC, cesarean, breech delivery, external cephalic version, shoulder dystocia examination. The method consists of diluting 10 units of synthetic oxytocin into a liter of dextrose solution. The resulting solution (10 mU/mL) is infused by counting drops per minute. Approximately 15-20 drops are equivalent to 1 mL. The infusion is begun at 10 drops per minute, and the dosage is increased every 15 minutes by 10 drops per minute to a maximum of 60 drops per minute. Thus, the initial dosage of oxytocin is approximately 6 mU/min, and the maximum dosage is approximately 40 mU/min. Oxytocin is not used if meconium is present or for more than 6 hours. A nurse attends each woman in labor, and monitoring of the fetus is by intermittent auscultation. Electronic monitors are restricted to cases in which fetal blood sampling is deemed necessary, such as when meconium is present or an abnormal heart rate is detected by auscultation. Fetal distress is mainly diagnosed by fetal blood sampling, not by the interpretation of continuous electronic FHR tracings. Cesarean delivery is performed if delivery has not occurred or is not imminent at 12 hours after admission or, rarely, for fetal distress.

The experience of the National Maternity Hospital in Dublin with active management of labor includes a low cesarean rate without untoward events. All reports emanating from Dublin have been descriptive in nature. Recently, two randomized clinical trials in the United States reported apparently conflicting results. One report noted a 26% reduction in cesarean deliveries for women assigned to active management. However, another group found no difference in cesarean deliveries between active management and usual care groups. It is important to note that in both studies active management of labor was associated with reduced time in labor.

LABOR STIMULATION

The stimulation of uterine contractions may be characterized as labor induction or labor augmentation. Induction of labor implies stimulation of uterine contractions in their prior absence, with or without ruptured fetal membranes. Labor induction may be elective or indicated. Elective induction of labor is defined as the initiation of labor solely for convenience.

Induction or augmentation of labor may be initiated only after a physician has evaluated the woman's condition, determined that induction or augmentation is beneficial to the mother or fetus, recorded the indication.

Techniques for induction of labor may be divided into surgical or medical. Surgical techniques include stripping of membranes or amniotomy. Stripping of fetal membranes involves bluntly separating the chorioamnionic membrane from the wall of the cervix and the lower uterine segment. The efficacy of induction of labor by stripping membranes has not been established. Risks include potential infection, bleeding from previously undiagnosed placenta previa or low-lying placenta, and the accidental rupture of membranes.

Timing of amniotomy is very important for maximizing the number of vaginal deliveries and for reducing the number of operative deliveries during labor induction. Once amniotomy is performed, the patient is committed to delivery. Induction of labor in a woman with a favorable cervix by amniotomy or a combination of amniotomy and oxytocin is widely accepted and used. Many obstetricians will perform amniotomy only after regular contractions are established.